Winning votes intuitive?

Sun Mar 31 22:53:14 PST 2002

Rob LeGrand said:

I come from a mathematical background; specifically, I'm a student of game
theory. So I tend to be pessimistic: I'd rather assume that whatever voters
could do to help themselves, they will do. The argument that any insincere
strategy that works under margins also works by flipping a coin under
winning-votes is very persuasive to me that winning-votes's advantages are

I reply:

Ok, winning in violation of majority rule, by truncation, in the way that 
happen in margins methods--how will that happen in wv methods
by flipping a coin?

When you said that wv doesn't guarantee anything that margins
doesn't guarantee, I told you of some guarantees, which I call
SFC & GSFC. In CSSD(wv), BeatpathWinner(wv), or Ranked-Pairs(wv),
if X is in the sincere Smith set, and Y is not, and if a majority
prefer X to Y, and vote sincerely, and if no one falsifies a preference,
then Y can't win. Not even if someone flips a coin :-)

In PC(wv), that guarantee applies if X is the sincere CW.

(Of course CSSD & BeatpathWinner are just different definitions and
procedures that always choose the same winner).

Yes, I know that you think that, with wv, voters who'd otherwise
have only truncated would order-reverse. Even if the necessary number
of people were inclined to do that, which is really doubtful, it
would carry a great danger of backfiring. To persuade so many people
to do something so devious, would require a big public persuasion
campaign. The intended victims of the order-reversal would hear about
it, and of course they wouldn't rank the candidate whom the
reversal is intended to benefit, with the result that the order-reversal
would backfire badly for its perpetrators.

One thing about offensive order-reversal strategy in wv methods is
that it only works if its victims are trying to help their victimizers'

Anyway, all it would take would be one disastrous attempt at
reversal strategy, and then the mere possibility that voters might
be using defensive truncation would make order-reversal strategy
very rare. Except that it will be rare anyway.

Rob LG continues:

In addition, I can't think of any methods besides winning-votes methods for
which an optimal zero-information ballot is insincere. Even under plurality,
the best vote is sincere in the absence of poll information. I see this as a
serious defect of winning-votes, especially in a local or nonpartisan 
or if you're not one to trust polls, but again, I can understand that some
would disagree.

I reply:

If the insincere voting that you're referring to is ranking in
different rank positions candidates whom you sincerely rate equally,
do you really think that's important? Remember, you're indifferent
between those candidates. Why would it bother you if you have
incentive to rank one over the other?

If you're referring to the strategy of ranking some candidates
together in 1st place, even though you don't sincerely rate them
equal--for one thing, though that satisfies my definition of
insincerity, a definition that's useful for criteria, not voting
preferences that you perceive doesn't sound very insincere, compared
to voting unfelt preferences (which also sounds pretty unimportant,
when one is indifferent between the candidates concerned). I don't
call those serious strategy problems for that voter.

As I explained before, the fact that you can gain by equal-ranking
some best candidates whom you don't sincerely rate equal isn't something
that should distress you, or put you in a bind. You aren't defensive-
strategically forced to do that. You merely can gain by it in a 0-info
election. None of our elections are 0-info, by the way.

If you expect an ambiguous situation, a natural circular tie in which
your worst candidates are in a cycle with your best, then you don't
have much confidence in the other voters. I mean, if those worse
candidates are so bad, are they really likely to be in a natural
circular tie with the best candidates? And if not, then the
situation where you could gain by promoting some good but sub-best
candidates up to 1st place wouldn't exist. In any case, you're
talking about a possible gain in a natural circular tie, whereas
margins makes drastic defensive strategy necessary to protect a sincere
CW or to protect majority rule.

Rob LG continues:

One thing that I never understood about Mike's reasoning (I'm sure Mike will
correct me if I'm wrong on any point) is that he likes Approval because it
never forces a voter to vote a less-liked candidate over a more-liked

I reply:


Rob LG continues:

, but he likes winning-votes methods because, in a sense, they *do*
sometimes force a voter to engage in strategic reversal, where the less 
strategy of voting ties might work under margins.

I reply:

I suppose a burglar could sue you because you were mean enough to
force him to break your window, thereby cutting himself, because
you locked your door.

WV methods don't force anyone to do order-reversal. Someone could
try it, on the chance that they could gain from it, by taking victory
from a sincere CW. But no one needs to order-reverse in order to
protect a sincere CW or to enforce majority rule--as they often
will have to in margins methods. You're interested in voters forced
to order-reverse? Margins is the method that will do that. Sometimes,
with margins, you'll be sorry when a CW loses, or a big majority
rule violation occurs because you didn't bury your favorite by
voting someone over him/her.

Rob LG, if you'll check the introductory web-page for EM, it points
out that it isn't productive to repeat refuted arguments. We've been
over all this before.

Rob LG continues:

He likes that truncation,
voting ties among the lower ranks, isn't a good strategy under winning-votes

I reply:

Yes, it isn't an offensive strategy that works. It won't steal
the election from a sincere CW, or violate majority rule in the
way that I've pointed out that margins will.

Rob LG continues:

but doesn't seem to mind as much that voting effective ties by coin-flipping 
outright reversal do the job for a wily voter just as well as truncation.

I reply:

What job will it do? Will it cause the violations that truncation
will cause in margins? Ok, if voters indifferent between A & B
all voted A over B, then, if B is sincere CW, they could create
a strategic circular tie.

But they couldn't thereby make B be beaten by majority,
unless there's already a huge amount of indifference between
that CW & A.
And if B beats their favorite by majority, as a CW would be likely
to do, then they therefore won't win by their strategy, under wv.

As for flipping coins, that of course would most likely have no
effect in a public election, as the coin-flips and the resulting
AB votes would tend to cancel out.

Rob LG continues:

also doesn't seem worried about top-of-the-ballot "truncation". His aims 
somewhat contradictory to me.

I reply:

What's top-of-the-ballot truncation? Do you mean equally ranking
some of your favorite candidates even though you don't sincerely
rate them equal? I've talked, in this message, and before, about
why I don't consider that a serious problem. Having the possibility
of gaining that way in certain natural circular ties is very different
from needing to do that in order to protect a sincere CW or to protect
majority rule, as often happens in margins.

Or do you mean defensive truncation? If so, I remind you that
defensive order-reversal is often necessary in margins.

Rob LG continues:

It should be remembered that any possible method will have serious strategy
problems when the electorate is well-informed and there is no sincere 

I reply:

"Every method has problems, and so we shouldn't try to minimize
the magnitude of the problems"--That sounds like what we hear
from our IRV friends.

Mike Ossipoff

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